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Lilac Bushes Dieing #877903

Asked July 19, 2024, 11:00 AM EDT

I am on an HOA board in Cambridge, MN. and many of our Lilac bushes/shrubs, as well as other bushes, but mainly lilacs are dieing and being over taken by an invasive weed which causes leaves to curl, etc. Some residents think it's from the chemical 2,4-D, but hard to say, as it could be a fungus too? Was hoping someone could come out and determine what it is, as if the chemical then we want lawn guy to use something else. If a fungus, how do we treat that to save bushes? If chemical, what's a safer affordable option?

Isanti County Minnesota

Expert Response

Hi Tammy,

We are Master Gardener volunteers and don't make house calls. Sorry. Your best bet is to confer with a landscape company that does work with shrub health.

Herbicide damaged plants exhibit symptoms like twisted stems and contorted leaves. Here's some photos of lilacs with herbicide damage:

https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/lilac/leavescupped.html

Many lilacs are getting bacterial blight this year. Here's a couple good pages on bacterial blight:

https://yardandgarden.extension.iastate.edu/encyclopedia/lilac-bacterial-blight

http://plantclinic.cornell.edu/factsheets/lilacbacterialblight.pdf

If you don't think this is blight, this page may help you narrow the cause:

https://apps.extension.umn.edu/garden/diagnose/plant/deciduous/lilac/

The only way to determine if this is blight is to have a sample of the plant tested. The Plant Disease Clinic at the U of M does this, but for a price. You can find more information here:

https://pdc.umn.edu/

Sorry I can't give you a definitive answer. Good luck.

MJ Replied July 19, 2024, 5:58 PM EDT

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